WO2017217276A1

WO2017217276A1 - Thermosetting epoxy resin composition and production method for same

Info

Publication number: WO2017217276A1
Application number: PCT/JP2017/020906
Authority: WO
Inventors: 和伸神谷
Original assignee: デクセリアルズ株式会社
Priority date: 2016-06-15
Filing date: 2017-06-06
Publication date: 2017-12-21
Also published as: KR20190019969A; TWI717525B; US10669458B2; JP2017222781A; TW201815869A; CN109312059A; JP6948114B2; KR102277065B1; CN109312059B; US20190203087A1

Abstract

A thermosetting epoxy resin composition containing: epoxy resin; a latent curing agent being porous particles comprising polyuria resin and holding aluminium chelate; and boric acid.

Description

Thermosetting epoxy resin composition and method for producing the same

The present invention relates to a thermosetting epoxy resin composition and a method for producing the same.

Conventionally, an aluminum chelate-based latent curing agent in which an aluminum chelate-based curing agent is held in a porous resin obtained by interfacial polymerization of a polyfunctional isocyanate compound has been proposed as a curing agent that exhibits low-temperature rapid curing activity for epoxy resins. (For example, see Patent Documents 1 and 2).
In the thermosetting epoxy resin composition using these latent curing agents, when the arylsilanol is used in combination, the aluminum chelate and the arylsilanol work together to cationically cure the epoxy resin.

By the way, in the thermosetting epoxy resin composition, there is a technique of blending an aluminum chelate, an alkylphenylpolysiloxane, and an alkoxyboron compound for the purpose of imparting weather resistance and preparing a coating film that can be applied relatively thickly. It has been proposed (see, for example, Patent Document 3).

In recent years, further low-temperature curability of a thermosetting epoxy resin composition using a latent curing agent has been demanded. However, there is a problem that, when trying to improve the low temperature curability, the viscosity during storage tends to increase.

Japanese Patent No. 5458596 Japanese Patent No. 5707661 JP 63-189472 A

This invention makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, an object of the present invention is to provide a thermosetting epoxy resin composition that can improve low-temperature curability without adversely affecting the viscosity increase during storage, and a method for producing the same.

Means for solving the problems are as follows. That is,
<1> an epoxy resin;
A latent curing agent composed of polyurea resin and porous particles holding aluminum chelate;
A thermosetting epoxy resin composition comprising boric acid.
<2> The thermosetting epoxy resin composition according to <1>, further including an organosilane compound.
<3> The thermosetting epoxy resin composition according to <2>, wherein the organic silane compound contains at least one of an arylsilanol compound and a silane coupling agent.
<4> The boric acid is derived from a boric acid ester in preparing the thermosetting epoxy resin composition,
When preparing the thermosetting epoxy resin composition, the mass ratio of the organosilane compound to the borate ester (organosilane compound: borate ester) is 1: 3 to 3 1 is the thermosetting epoxy resin composition according to any one of <2> to <3>.
<5> The thermosetting epoxy resin composition according to any one of <1> to <4>, wherein the epoxy resin contains an alicyclic epoxy resin.
<6> The thermosetting epoxy resin composition according to <5>, wherein the alicyclic epoxy resin contains at least one of compounds represented by the following structural formulas.

<7> The thermosetting epoxy resin composition according to any one of <1> to <6>, wherein the porous particles further include a vinyl resin as a constituent component.
<8> The thermosetting epoxy resin composition according to any one of <1> to <7>, wherein a surface of the porous particle has a reaction product of an alkoxysilane coupling agent.
<9> The method for producing a thermosetting epoxy resin composition according to any one of <1> to <8>,
It is a manufacturing method of the thermosetting epoxy resin composition characterized by including the mixing process which mixes the said epoxy resin, the said latent hardener, and boric acid ester.
<10> The method for producing a thermosetting epoxy resin composition according to <9>, wherein an organic silane compound is further mixed in the mixing step.
<11> The heat according to <10>, wherein a mass ratio of the organosilane compound to the borate ester (organosilane compound: borate ester) in the mixing step is 1: 3 to 3: 1. It is a manufacturing method of a curable epoxy resin composition.

According to the present invention, the thermosetting epoxy resin composition capable of solving the above-mentioned problems in the past, achieving the object, and improving low-temperature curability without adversely affecting the viscosity increase during storage, And a manufacturing method thereof.

FIG. 1 shows DSC measurement results. FIG. 2 shows DSC measurement results. FIG. 3 shows DSC measurement results. FIG. 4 shows DSC measurement results.

(Thermosetting epoxy resin composition)
The thermosetting epoxy resin composition of the present invention contains at least an epoxy resin, a latent curing agent, and boric acid, preferably contains an organosilane compound, and further contains other components as necessary. To do.

The present inventor has intensively studied to provide a thermosetting epoxy resin composition capable of improving low-temperature curability without adversely affecting the viscosity increase during storage. As a result, in the thermosetting epoxy resin composition containing the epoxy resin and the latent curing agent, the viscosity at the time of storage can be obtained by using boric acid instead of the organic silane compound or in combination with the organic silane compound. It has been found that low temperature curability can be improved without adversely affecting the rise, and the present invention has been completed.
In the above-mentioned Japanese Patent Application Laid-Open No. 63-189472, a technique for blending an aluminum chelate, an alkylphenylpolysiloxane, and an alkoxyboron compound in a thermosetting epoxy resin composition is proposed. There is no suggestion that the low-temperature curability can be improved without adversely affecting the viscosity increase.

<Epoxy resin>
There is no restriction | limiting in particular as said epoxy resin, According to the objective, it can select suitably, For example, a glycidyl ether type epoxy resin, an alicyclic epoxy resin, etc. are mentioned.

The glycidyl ether type epoxy resin may be, for example, liquid or solid, and preferably has an epoxy equivalent of usually about 100 to 4000 and having two or more epoxy groups in the molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, ester type epoxy resin and the like can be mentioned. Among these, bisphenol A type epoxy resins can be preferably used from the viewpoint of resin characteristics. These epoxy resins also include monomers and oligomers.

The alicyclic epoxy resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, vinylcyclopentadiene dioxide, vinylcyclohexene mono- to dioxide, dicyclopentadiene oxide, epoxy- [epoxy-oxaspiro C _8-15 alkyl] -cycloC _5-12 alkane (for example, 3,4-epoxy-1- [8,9-epoxy-2,4-dioxaspiro [5.5] undecan-3-yl] -cyclohexane, etc. ), 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, epoxy C _5-12 cycloalkyl C _1-3 alkyl-epoxy C _5-12 cycloalkanecarboxylate (eg, 4,5- Epoxycyclooctylmethyl-4 ', 5'-epoxycyclooct Emissions carboxylate), bis _{(C 1-3} alkyl epoxy _{C 5-12} cycloalkyl _{C 1-3} alkyl) dicarboxylates (e.g., bis (2-methyl-3,4-epoxycyclohexylmethyl) adipate, etc.), etc. Is mentioned.

In addition, as an alicyclic epoxy resin, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate [trade name: Celoxide #, manufactured by Daicel Corporation, because it is easily available as a commercial product. 2021P; epoxy equivalent of 128 to 140] is preferably used.

In the above examples, the description of C _8-15 , C _5-12 , and C _1-3 includes 8 to 15 carbon atoms, 5 to 12 carbon atoms, and 1 to 3 carbon atoms, respectively. It means that there is a range of compound structures.

A structural formula of an example of the alicyclic epoxy resin is shown below.

The content of the epoxy resin in the thermosetting epoxy resin composition is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 30% by mass to 99% by mass, and more preferably 50% by mass to 98%. % By mass is more preferable, and 70% by mass to 97% by mass is particularly preferable.
Here, the numerical range defined using “to” in this specification is a range including a lower limit value and an upper limit value. That is, “30 mass% to 99 mass%” is synonymous with “30 mass% to 99 mass%”.

<Latent curing agent>
The latent curing agent is a porous particle.
The porous particles are composed of at least a polyurea resin, and may further contain a vinyl resin as a constituent component.
The porous particles retain at least an aluminum chelate.
The porous particles retain the aluminum chelate in the pores, for example. In other words, the aluminum chelate is incorporated and held in the fine pores present in the porous particle matrix composed of the polyurea resin.
The surface of the porous particle preferably has a reaction product of an alkoxysilane coupling agent.

<< Polyurea resin >>
The polyurea resin is a resin having a urea bond in the resin.
The polyurea resin constituting the porous particles can be obtained, for example, by polymerizing a polyfunctional isocyanate compound in an emulsion. Details thereof will be described later. The polyurea resin may have a bond derived from an isocyanate group and a bond other than a urea bond, such as a urethane bond, in the resin.

<< Vinyl resin >>
The vinyl resin is a resin obtained by polymerizing a radical polymerizable vinyl compound.
The vinyl resin improves the mechanical properties of the porous particles. Thereby, the thermal responsiveness at the time of hardening of the epoxy resin in a thermosetting epoxy resin composition, especially a sharp thermal responsiveness in a low-temperature area | region is realizable.

The vinyl resin contains, for example, a radical polymerizable vinyl compound in an emulsion containing a polyfunctional isocyanate compound, and the radical polymerization is performed simultaneously with the polymerization of the polyfunctional isocyanate compound in the emulsion. It can be obtained by radical polymerization of a functional vinyl compound.

<< Aluminum chelate >>
Examples of the aluminum chelate include a complex compound in which three β-keto enolate anions coordinated to aluminum represented by the following general formula (1). Here, the alkoxy group is not directly bonded to aluminum. This is because when it is directly bonded, it is easily hydrolyzed and is not suitable for the emulsification treatment in producing the porous particles.

In the general formula (1), R ¹ , R ² and R ³ each independently represents an alkyl group or an alkoxyl group.
Examples of the alkyl group include a methyl group and an ethyl group.
Examples of the alkoxyl group include a methoxy group, an ethoxy group, and an oleyloxy group.

Examples of the complex compound represented by the general formula (1) include aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum monoacetylacetonate bis (ethylacetoacetate), and aluminum monoacetylacetonate. Examples thereof include bis (oleyl acetoacetate).

The content of the aluminum chelate in the porous particles is not particularly limited and can be appropriately selected depending on the purpose.

The average pore diameter of the pores of the porous particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 nm to 300 nm, more preferably 5 nm to 150 nm.

<Reaction product>
The reaction product is obtained by reacting an alkoxysilane coupling agent.
The reaction product is present on the surface of the porous particles.

The reaction product is preferably obtained by an inactivation step described in detail later.

The latent curing agent is preferably particulate.
The average particle diameter of the latent curing agent is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5 μm to 20 μm, more preferably 1 μm to 10 μm, and particularly preferably 1 μm to 5 μm. .

There is no restriction | limiting in particular as content of the said latent hardener in the said thermosetting type epoxy resin composition, Although it can select suitably according to the objective, 1 mass part with respect to 100 mass parts of said epoxy resins Is preferably 70 parts by mass, and more preferably 1 part by mass to 50 parts by mass. If the content is less than 1 part by mass, the curability may be reduced, and if it exceeds 70 parts by mass, the resin properties (for example, flexibility) of the cured product may be reduced.

<< Method for producing latent curing agent >>
The manufacturing method of the latent curing agent includes, for example, at least a porous particle preparation step and an inactivation step, and further includes other steps as necessary.

-Porous particle production process-
The porous particle preparation process includes at least an emulsion preparation process and a polymerization process, preferably includes an additional filling process, and further includes other processes as necessary.

--Emulsion preparation process--
The emulsion preparation process is not particularly limited as long as it is a process for obtaining an emulsion by emulsifying a liquid obtained by mixing an aluminum chelate, a polyfunctional isocyanate compound, and preferably an organic solvent. For example, it can be performed using a homogenizer.
When the resin constituting the porous particles contains not only a polyurea resin but also a vinyl resin, the liquid further contains a radical polymerizable vinyl compound and a radical polymerization initiator.

Examples of the aluminum chelate include the aluminum chelate in the explanation of the latent curing agent of the present invention.

The size of the oil droplets in the emulsion is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5 μm to 100 μm.

--- Polyfunctional isocyanate compound ---
The polyfunctional isocyanate compound is a compound having two or more isocyanate groups, preferably three isocyanate groups in one molecule. More preferable examples of such a trifunctional isocyanate compound include a TMP adduct of the following general formula (2) obtained by reacting 3 mol of a diisocyanate compound with 1 mol of trimethylolpropane, and the following general formula obtained by self-condensing 3 mol of a diisocyanate compound. Examples include the isocyanurate body of the formula (3) and the burette body of the following general formula (4) in which the remaining 1 mole of diisocyanate is condensed to the diisocyanate urea obtained from 2 moles of 3 moles of the diisocyanate compound.

In the general formulas (2) to (4), the substituent R is a portion excluding the isocyanate group of the diisocyanate compound. Specific examples of such diisocyanate compounds include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, m-xylylene diisocyanate, hexamethylene diisocyanate, hexahydro-m-xylylene diisocyanate, isophorone diisocyanate, methylene diphenyl-4. , 4'-diisocyanate and the like.

The mixing ratio of the aluminum chelate and the polyfunctional isocyanate compound is not particularly limited and can be appropriately selected according to the purpose. However, if the amount of the aluminum chelate is too small, the epoxy resin to be cured When the curability is lowered and the amount is too large, the potential of the resulting latent curing agent is lowered. In this respect, the aluminum chelate is preferably 10 to 500 parts by mass, more preferably 10 to 300 parts by mass with respect to 100 parts by mass of the polyfunctional isocyanate compound.

---Organic solvent---
There is no restriction | limiting in particular as said organic solvent, Although it can select suitably according to the objective, A volatile organic solvent is preferable.
The organic solvent is a good solvent for each of the aluminum chelate, the polyfunctional isocyanate compound, the polyfunctional radical polymerizable vinyl compound, and the radical polymerization initiator (the solubility of each is preferably 0.1 g / ml (organic solvent). It is preferable that the solvent does not substantially dissolve in water (the solubility of water is 0.5 g / ml (organic solvent) or less) and has a boiling point of 100 ° C. or less under atmospheric pressure. Specific examples of such volatile organic solvents include alcohols, acetate esters, ketones and the like. Among these, ethyl acetate is preferable in terms of high polarity, low boiling point, and poor water solubility.

The amount of the organic solvent used is not particularly limited and can be appropriately selected depending on the purpose.

---- Radically polymerizable vinyl compound ---
The radical polymerizable vinyl compound is a compound having a radical polymerizable carbon-carbon unsaturated bond in the molecule.
The radical polymerizable vinyl compound includes so-called monofunctional radical polymerizable compounds and polyfunctional radical polymerizable compounds.
The radical polymerizable vinyl compound preferably contains a polyfunctional radical polymerizable compound. This is because by using a polyfunctional radically polymerizable compound, it becomes easier to realize sharp thermal responsiveness in a low temperature region. Also from this meaning, the radical polymerizable vinyl compound preferably contains 30% by mass or more, more preferably 50% by mass or more of the polyfunctional radical polymerizable compound.

Examples of the monofunctional radical polymerizable compound include monofunctional vinyl compounds (for example, styrene and methylstyrene), monofunctional (meth) acrylate compounds (for example, butyl acrylate), and the like.
Examples of the polyfunctional radical polymerizable compound include polyfunctional vinyl compounds (eg, divinylbenzene, divinyl adipate, etc.), polyfunctional (meth) acrylate compounds (eg, 1,6-hexanediol diacrylate, Methylolpropane triacrylate and the like).
Among these, polyfunctional vinyl compounds, particularly divinylbenzene, can be preferably used from the viewpoints of latency and heat responsiveness.

In addition, the polyfunctional radically polymerizable compound may be composed of a polyfunctional vinyl compound and a polyfunctional (meth) acrylate compound. By using together in this way, the effect that a thermal responsiveness is changed or a reactive functional group can be introduce | transduced is acquired.

The amount of the radical polymerizable vinyl compound is not particularly limited and may be appropriately selected depending on the intended purpose. It is preferably 1 to 80 parts by mass with respect to 100 parts by mass of the polyfunctional isocyanate compound. 10 parts by mass to 60 parts by mass is more preferable.

--- Radical polymerization initiator ---
Examples of the radical polymerization initiator include peroxide initiators and azo initiators.

The blending amount of the radical polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose. It is 0.1 to 10 parts by mass with respect to 100 parts by mass of the radical polymerizable vinyl compound. It is preferably 0.5 parts by mass to 5 parts by mass.

--- Polymerization process--
The polymerization treatment is not particularly limited as long as it is a treatment for obtaining porous particles by polymerizing the polyfunctional isocyanate compound in the emulsion, and can be appropriately selected according to the purpose.

The porous particles hold the aluminum chelate.

In the polymerization treatment, a part of the isocyanate group of the polyfunctional isocyanate compound is hydrolyzed to become an amino group, and the amino group and the isocyanate group of the polyfunctional isocyanate compound react to form a urea bond. A polyurea resin is obtained. Here, when the polyfunctional isocyanate compound has a urethane bond, the resulting polyurea resin also has a urethane bond, and the polyurea resin produced at that point can also be referred to as a polyureaurethane resin. .

In the case where the emulsion contains the radical polymerizable vinyl compound and the radical polymerization initiator, in the polymerization treatment, the polyfunctional isocyanate compound is polymerized and at the same time, the presence of the radical polymerization initiator is present. Under the above, the radical polymerizable vinyl compound causes radical polymerization.
Therefore, the obtained porous particles contain a polyurea resin and a vinyl resin as constituent resins.

The polymerization time in the polymerization treatment is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 hour to 30 hours, and more preferably 2 hours to 10 hours.
The polymerization temperature in the polymerization treatment is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 30 ° C. to 90 ° C., more preferably 50 ° C. to 80 ° C.

--- Additional filling process ---
The additional filling process is not particularly limited as long as it is a process of additionally filling the porous particles obtained by the polymerization process with an aluminum chelate, and can be appropriately selected according to the purpose. For example, aluminum Examples include a method of removing the organic solvent from the solution after the porous particles are immersed in a solution obtained by dissolving a chelate in an organic solvent.

The amount of aluminum chelate retained by the porous particles is increased by performing the additional filling process. The porous particles additionally filled with aluminum chelate can be crushed into primary particles by a known crushing apparatus after being filtered, washed and dried as necessary.

The aluminum chelate that is additionally filled in the additional filling process may be the same as or different from the aluminum chelate that is blended in the liquid to be the emulsion. For example, since water is not used in the additional filling process, the aluminum chelate used in the additional filling process may be an aluminum chelate in which an alkoxy group is bonded to aluminum. Examples of such aluminum chelates include diisopropoxy aluminum monooleyl acetoacetate, monoisopropoxy aluminum bis (oleyl acetoacetate), monoisopropoxy aluminum monooleate monoethyl acetoacetate, diisopropoxy aluminum monolauryl acetoacetate. And diisopropoxyaluminum monostearyl acetoacetate, diisopropoxyaluminum monoisostearyl acetoacetate, monoisopropoxyaluminum mono-N-lauroyl-β-alanate monolauryl acetoacetate and the like.

The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include the organic solvents exemplified in the description of the emulsion preparation process. The preferred embodiment is also the same.

The method for removing the organic solvent from the solution is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the method of heating the solution to the boiling point of the organic solvent or lowering the solution. The method etc. are mentioned.

The content of the aluminum chelate in the solution obtained by dissolving the aluminum chelate in the organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose, but is 10% by mass to 80% by mass. Preferably, 10% by mass to 50% by mass is more preferable.

-Inactivation process-
The deactivation step is not particularly limited as long as it is a step of providing a reaction product of an alkoxysilane coupling agent on the surface of the porous particles, and can be appropriately selected according to the purpose. The porous particles are preferably immersed in a solution containing an alkoxysilane coupling agent and an organic solvent and reacted with the alkoxysilane coupling agent.

The porous particles are considered to have an aluminum chelate not only on the inside but also on the surface due to its structure. However, most of the surface aluminum chelate is inactivated by water present in the polymerization system during the interfacial polymerization. Therefore, the porous particles can acquire the potential without requiring the deactivation step (that is, even if the surface does not have a reaction product of an alkoxysilane coupling agent).
However, when an alicyclic epoxy resin having high reactivity is used as the epoxy resin, the thermosetting epoxy resin composition using the latent curing agent that has not undergone the inactivation step is greatly thickened over time. To do. Therefore, it is considered that a part of the aluminum chelate on the surface of the porous particle is not inactivated and maintains the activity.
Therefore, it is preferable to inactivate the aluminum chelate present on the surface of the porous particles with an alkoxysilane coupling agent as described below.

--- Alkoxysilane coupling agent--
The alkoxysilane coupling agent is classified into two types as described below.

The first type reacts with the active aluminum chelate on the surface of the porous particles to produce an aluminum chelate-silanol reactant, thereby reducing the electron density of oxygen adjacent to the aluminum atom (in other words, It is a type of silane coupling agent whose activity is lowered by lowering the acidity of hydrogen bonded to oxygen, in other words, lowering the polarizability between oxygen and hydrogen. Examples of this type of silane coupling agent include an alkoxysilane coupling agent having an electron donating group bonded to a silicon atom, preferably an alkylalkoxysilane coupling agent having an alkyl group. Specific examples include methyltrimethoxysilane, n-propyltrimethoxysilane, hexyltrimethoxysilane and the like.

The second type is a silane coupling agent of which the activity is lowered by covering the surface with an epoxy polymer chain generated by reacting the active aluminum chelate of the porous particles with an epoxy group in the molecule. An epoxy silane coupling agent is mentioned as this type of silane coupling agent. Specifically, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (KBM-303, Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropyltrimethoxysilane (KBM-403, Shin-Etsu Chemical ( Etc.).

--Organic solvent--
There is no restriction | limiting in particular as said organic solvent, Although it can select suitably according to the objective, A nonpolar solvent is preferable. Examples of the nonpolar solvent include hydrocarbon solvents. Examples of the hydrocarbon solvent include toluene, xylene, cyclohexane and the like.

The content of the alkoxysilane coupling agent in the solution is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5% by mass to 80% by mass.

The temperature of the solution in the inactivation step is not particularly limited and may be appropriately selected depending on the intended purpose. The aggregation of the porous particles and the outflow of the aluminum chelate from the porous particles 10 to 80 ° C is preferable, and 20 to 60 ° C is more preferable.
The immersion time in the inactivation step is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 hour to 48 hours, and more preferably 5 hours to 30 hours.

In the inactivation step, the solution is preferably stirred.

The latent curing agent obtained through the inactivation step can be filtered, washed and dried as necessary, and then pulverized into primary particles by a known pulverizer.

<Boric acid>
The boric acid (B (OH) ₃ ) has a function of starting cationic polymerization of the epoxy resin in cooperation with the aluminum chelate held in the latent curing agent.

There is no restriction | limiting in particular as content of the said boric acid in the said thermosetting epoxy resin composition, Although it can select suitably according to the objective, 1 mass part with respect to 100 mass parts of the said latent hardeners. Is preferably 500 parts by mass, more preferably 30 parts by mass to 400 parts by mass, and more preferably 50 parts by mass to 300 parts by mass.

When preparing the thermosetting epoxy resin composition, the boric acid may be added, but it is preferable to add a boric acid ester in terms of ease of handling. The borate ester reacts with moisture in the system to become boric acid. As a result, when the thermosetting epoxy resin composition is prepared by blending the boric acid ester, the boric acid is present in the thermosetting epoxy resin composition.

As said boric acid ester, the compound represented by the following general formula (X) is mentioned, for example.
B (OR) ₃ ... General formula (X)
However, in the general formula (X), R may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group.

There is no restriction | limiting in particular as a compounding quantity at the time of mix | blending the said boric acid ester with the said thermosetting epoxy resin composition, Although it can select suitably according to the objective, With respect to 100 mass parts of said latent hardening agents. 1 to 500 parts by mass is preferable, and 30 to 400 parts by mass is more preferable.

<Organic Silane Compound>
As described in paragraphs 0007 to 0010 of JP-A No. 2002-212537, the organic silane compound cooperates with the aluminum chelate held in the latent curing agent to perform cationic polymerization of the epoxy resin. Has the function of starting. Therefore, the effect of accelerating the curing of the epoxy resin can be obtained by using such an organosilane compound in combination. Examples of such organic silane compounds include highly sterically hindered silanol compounds and silane coupling agents having 1 to 3 lower alkoxy groups in the molecule. In the silane coupling agent molecule, a group having reactivity to the functional group of the thermosetting resin, for example, vinyl group, styryl group, acryloyloxy group, methacryloyloxy group, epoxy group, amino group, mercapto group However, since the latent curing agent of the present invention is a cationic curing agent, the amino group or the mercapto group substantially generates the generated cationic species. Can be used when not captured.

In the thermosetting epoxy resin composition, the curing start temperature (for example, the heat generation start temperature in DSC measurement) can be lowered by using the boric acid and the organosilane compound in combination. The inventor considers the reason as follows.
In the case of active species formation using an aluminum chelate and an organosilane compound, a two-step reaction is required, and thus the curing rate may be slow.
On the other hand, in the case of active species formation by an aluminum chelate and boric acid, a ligand exchange reaction occurs, and an unshared electron pair on the oxygen atom of the hydroxyl group of the complex formed thereby coordinates with an Al atom, thereby generating hydrogen. The acid strength of the atoms increases, and it acts as an active species. In the case of this reaction, the formation of active species is a one-step reaction, so that the activation temperature can be lowered. However, the absolute value of the acid strength of the active species formed is lower than the Bronsted acid formed by the organosilane compound.
Therefore, it is considered that by using boric acid and the organosilane compound in combination, the advantages of both can be revealed and the curing start temperature (for example, the heat generation start temperature in DSC measurement) can be lowered.

The highly sterically hindered silanol compound is an aryl silanol compound having an aryl group, unlike a conventional silane coupling agent having a trialkoxy group.

<< Arylsilanol compound >>
The arylsilanol compound is represented, for example, by the following general formula (A).

However, in the said general formula (A), m is 2 or 3, Preferably 3, However, The sum of m and n is 4. Ar is an aryl group which may have a substituent.
The arylsilanol compound represented by the general formula (A) is a monool or diol.

Ar in the general formula (A) is an aryl group which may have a substituent.
Examples of the aryl group include a phenyl group, a naphthyl group (eg, 1-naphthyl group, 2-naphthyl group, etc.), anthracenyl group (eg, 1-anthracenyl group, 2-anthracenyl group, 9-anthracenyl group, benz [ a] -9-anthracenyl group, etc.), phenaryl group (eg, 3-phenaryl group, 9-phenaryl group, etc.), pyrenyl group (eg, 1-pyrenyl group, etc.), azulenyl group, fluorenyl group, biphenyl group (eg, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, etc.), thienyl group, furyl group, pyrrolyl group, imidazolyl group, pyridyl group and the like. Among these, a phenyl group is preferable from the viewpoint of availability and cost. The m Ars may be the same or different, but are preferably the same from the viewpoint of availability.

These aryl groups can have, for example, 1 to 3 substituents.
Examples of the substituent include an electron withdrawing group and an electron donating group.
Examples of the electron withdrawing group include a halogen group (eg, chloro group, bromo group), trifluoromethyl group, nitro group, sulfo group, carboxyl group, alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, etc.). ), Formyl group and the like.
Examples of the electron donating group include an alkyl group (for example, methyl group, ethyl group, propyl group, etc.), an alkoxy group (for example, methoxy group, ethoxy group, etc.), a hydroxy group, an amino group, a monoalkylamino group (for example, , Monomethylamino group and the like), dialkylamino group (for example, dimethylamino group and the like) and the like.

Specific examples of the phenyl group having a substituent include, for example, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,6-dimethylphenyl group, 3,5-dimethylphenyl group, 2, 4-dimethylphenyl group, 2,3-dimethylphenyl group, 2,5-dimethylphenyl group, 3,4-dimethylphenyl group, 2,4,6-trimethylphenyl group, 2-ethylphenyl group, 4-ethylphenyl Group and the like.

In addition, the acidity of the hydroxyl group of a silanol group can be raised by using an electron withdrawing group as a substituent. By using an electron donating group as a substituent, the acidity of the hydroxyl group of the silanol group can be lowered. Therefore, the curing activity can be controlled by the substituent.
Here, the substituents may be different for each of the m Ars, but the substituents are preferably the same for the m Ars from the viewpoint of availability. Further, only some Ar may have a substituent, and other Ar may not have a substituent.

Of these, triphenylsilanol and diphenylsilanediol are preferable, and triphenylsilanol is particularly preferable.

<< Silane coupling agent >>
The silane coupling agent has 1 to 3 lower alkoxy groups in the molecule, and a group having reactivity in the molecule with respect to the functional group of the thermosetting resin, such as a vinyl group or a styryl group. , May have an acryloyloxy group, a methacryloyloxy group, an epoxy group, an amino group, a mercapto group, and the like. The coupling agent having an amino group or a mercapto group is used when the latent curing agent used in the present invention is a cationic curing agent, so that the amino group or mercapto group does not substantially trap the generated cationic species. can do.

Examples of the silane coupling agent include vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-styryltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-acryloxypropyl. Trimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β- (aminoethyl) -γ -Aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxy Shi And γ-chloropropyltrimethoxysilane.

There is no restriction | limiting in particular as content of the said organosilane compound in the said thermosetting epoxy resin composition, Although it can select suitably according to the objective, 1 mass with respect to 100 mass parts of said latent hardening agents. Part to 300 parts by weight is preferable, and 1 part to 100 parts by weight is more preferable.

When the boric acid is derived from a borate ester when preparing the thermosetting epoxy resin composition, the amount of the organosilane compound used when preparing the thermosetting epoxy resin composition, The mass ratio with respect to the amount of borate ester (organosilane compound: borate ester) is not particularly limited and may be appropriately selected depending on the intended purpose, but is 1: 3 to 3: 1. A ratio of 1: 2 to 2: 1 is more preferable.

<Other ingredients>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, an oxetane compound, a filler, a pigment, an antistatic agent etc. are mentioned.

<< Oxetane compound >>
In the thermosetting epoxy resin composition, the exothermic peak can be sharpened by using the oxetane compound in combination with the epoxy resin.
Examples of the oxetane compound include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 4,4′-bis [(3- Ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylic acid bis [(3-ethyl-3-oxetanyl)] methyl ester, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3 -(2-ethylhexyloxymethyl) oxetane, di [1-ethyl (3-oxetanyl)] methyl ether, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, oxetanylsilsesquioxy Sun, phenol novolac oxetane and the like.

The content of the oxetane compound in the thermosetting epoxy resin composition is not particularly limited and may be appropriately selected depending on the intended purpose. It is 10 to 100 parts by mass with respect to 100 parts by mass of the epoxy resin. Part by mass is preferable, and 20 to 70 parts by mass is more preferable.

(Method for producing thermosetting epoxy resin composition)
The method for producing the thermosetting epoxy resin composition of the present invention includes at least a mixing step of mixing the epoxy resin, the latent curing agent, and a boric acid ester, and further includes other steps as necessary. Including.

Examples of the epoxy resin include the epoxy resin exemplified in the description of the thermosetting epoxy resin composition of the present invention.
Examples of the latent curing agent include the latent curing agent exemplified in the description of the thermosetting epoxy resin composition of the present invention.
Examples of the boric acid ester include the boric acid esters exemplified in the description of the thermosetting epoxy resin composition of the present invention.

The mixing method in the mixing step is not particularly limited and can be appropriately selected depending on the purpose.

In the mixing step, it is preferable to further mix an organosilane compound.
As said organosilane compound, the said organosilane compound illustrated in description of the said thermosetting epoxy resin composition of this invention is mentioned, for example.
In the mixing step, the mass ratio of the organosilane compound to the borate ester (organosilane compound: borate ester) is preferably 1: 3 to 3: 1, and 1: 2 to 2: 1. It is more preferable that

Since the thermosetting epoxy resin composition of the present invention can improve low-temperature curability without adversely affecting the viscosity increase during storage, the pot life after blending can be extended, and the The burden of viscosity adjustment can be reduced.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Production Example 1)
<Manufacture of latent curing agent>
<< Porous particle production process >>
-Preparation of aqueous phase-
800 parts by weight of distilled water, 0.05 part by weight of a surfactant (Newlex RT, Nippon Oil & Fats Co., Ltd.), and 4 parts by weight of polyvinyl alcohol (PVA-205, Kuraray Co., Ltd.) as a dispersant. Into a 3 liter interfacial polymerization vessel equipped with a thermometer, the mixture was uniformly mixed to prepare an aqueous phase.

-Preparation of oil phase-
Next, 350 parts by mass of a 24 mass% isopropanol solution of aluminum monoacetylacetonate bis (ethyl acetoacetate) (Aluminum Chelate D, Kawaken Fine Chemical Co., Ltd.) and methylene diphenyl-4,4′-diisocyanate (3 mol) 49 parts by mass of a trimethylolpropane (1 mol) adduct (polyfunctional isocyanate compound, D-109, Mitsui Chemicals, Inc.) and 21 parts by mass of divinylbenzene (Merck) as a radical polymerizable vinyl compound, A radical polymerization initiator (Perroyl L, NOF Corporation) 0.21 part by mass was dissolved in 70 parts by mass of ethyl acetate to obtain an oil phase.

-Emulsification-
The prepared oil phase was put into the previously prepared aqueous phase and mixed and emulsified with a homogenizer (10000 rpm / 5 min: T-50, IKA Japan Co., Ltd.) to obtain an emulsion.

-polymerization-
The prepared emulsion was polymerized while stirring at 200 rpm at 80 ° C. for 6 hours. After completion of the reaction, the polymerization reaction liquid was allowed to cool to room temperature, and the produced polymer resin particles were filtered off by filtration and dried naturally to obtain a bulky curing agent. This bulk curing agent was pulverized into primary particles using a pulverizer (AO jet mill, Seishin Corporation) to obtain a particulate curing agent.

-Additional filling process-
The obtained particulate curing agent was impregnated with 40 parts by mass of a 24% by mass isopropanol solution of aluminum monoacetylacetobis (ethyl acetoacetate) (aluminum chelate D, Kawaken Fine Chemical Co., Ltd.) and 60 parts by mass of ethanol. After putting into the liquid and stirring at 30 ° C. for 6 hours, the particulate curing agent was filtered off and dried naturally to obtain a particulate curing agent (porous particles) additionally filled with aluminum chelate.

<< Inactivation process >>
3 parts by mass of the porous particles obtained in the porous particle production step were dissolved in 6 parts by mass of a solution [cyclohexane 24 parts by mass, n-propyltrimethoxysilane (KBM-3033, Shin-Etsu Chemical Co., Ltd.)]. The solution was put into 30 parts by mass and stirred at 30 ° C. for 20 hours at 200 rpm to inactivate the surface of the porous particles. After the inactivation was completed, the porous particles were filtered off from the treatment liquid by filtration and naturally dried to obtain a latent curing agent.

Example 1
<Preparation of thermosetting epoxy resin composition>
-material-
-Alicyclic epoxy resin (CEL2021P, Daicel Corporation) 100 parts by mass-Triphenylsilanol (Tokyo Chemical Industry Co., Ltd.) 2 parts by mass-Tributyl borate (Tokyo Chemical Industry Co., Ltd.) 1 part by mass-Production Example 1 part of latent curing agent prepared in 1

Using the above materials, a thermosetting epoxy resin composition was prepared by the following method.
After mixing triphenylsilanol with CEL2021P, the triphenylsilanol was dissolved by heating at 80 ° C. for 4 hours. Subsequently, after the resulting liquid was allowed to cool, other ingredients were blended, and the mixture was stirred at 2000 rpm for 1 minute with Awatori Netaro (AR-250: Sinky Co., Ltd.), thereby thermosetting epoxy resin composition. Got.

The structure of the alicyclic epoxy resin (CEL2021P) is as follows.

(Example 2 to Example 9, Comparative Example 1 to Comparative Example 2)
<Preparation of thermosetting epoxy resin composition>
In Example 1, the blending amounts of triphenylsilanol, KBM-403 (Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyltrimethoxysilane), and tributyl borate were changed to the blending amounts shown in Table 1 below. Except for this, a thermosetting epoxy resin composition was obtained in the same manner as in Example 1.

(Example 10)
<Preparation of thermosetting epoxy resin composition>
In Example 2, a thermosetting epoxy resin composition was obtained in the same manner as in Example 2 except that tributyl borate was changed to trimethyl borate.

(Example 11)
<Preparation of thermosetting epoxy resin composition>
A thermosetting epoxy resin composition was obtained in the same manner as in Example 2 except that triphenylsilanol was changed to 4-TFM silanol in Example 2.

4-TFM silanol is tris (4-trifluoromethylphenyl) silanol and is represented by the following structural formula.

4-TFM silanol can be synthesized, for example, according to the following known literature.
Shuzi Hayase, Yasunobu Onishi, Shuichi Suzuki, Moriyasu Wada. Photopolymerization of Cyclohexene Oxide by Use of Nitrobenzyl Triphenylsilyl Ether / Aluminum Compound Catalyst. Dependence of Catalyst Activity on the Structure of the Silyl Ether. Journal of Polymer Science: Part A: Polymer Chemistry 25, pp. 753-763, 1987

(DSC measurement)
DSC measurement was performed on the thermosetting epoxy resin compositions obtained in Examples 1 to 11 and Comparative Examples 1 and 2.
DSC measurement was performed under the following measurement conditions. The results are shown in Tables 2 to 5 and FIGS.
-Measurement condition-
・ Measuring device: Differential thermal analyzer (DSC6200, Hitachi High-Tech Science Co., Ltd.)
・ Evaluation amount: 5mg
・ Temperature increase rate 10 ℃ / 1min

From the DSC results, it can be seen that when triphenylsilanol is replaced with borate ester, the heat generation start temperature is lowered. Further, regarding the blending of Example 2 in which the tributyl borate blending amount was larger than that of triphenylsilanol, the exothermic peak temperature was lowered as well as the exothermic start temperature was lowered. However, in the case of the formulation of Example 3 in which triphenylsilanol was completely replaced with tributyl borate, a high temperature shift of the DSC chart was observed, so that the formulation in which a part of triphenylsilanol was replaced with tributyl borate started curing. It can be seen that it is effective in lowering the temperature.

Similarly, in the silane coupling agent system, it can be seen that the heat generation start temperature is lowered by partial replacement with borate ester. In the case of Example 4, the heat generation start temperature was lowered by about 9 ° C. and in the case of Example 5 by about 13 ° C.

(Viscosity change during storage)
The viscosity change of the thermosetting epoxy resin composition of Example 2, Example 5, and Comparative Example 1 was measured.

<Measurement method>
Viscosity was measured under the following measurement conditions. The results are shown in Table 6.
-Measurement condition-
・ Measurement device: SV-10 (vibrating viscometer A & D)
・ Aging temperature: Room temperature (25 ℃)
・ Viscosity measurement temperature: 20 ℃

In Table 6, “H” represents time. That is, 1H represents 1 hour. Therefore, for example, “1H viscosity” means the viscosity after 1 hour.

Examples 2 and 5 showed good liquid life in an alicyclic epoxy resin excellent in cationic polymerizability even though the DSC exotherm starting temperature was lowered (about 55 ° C. and 61 ° C.). In any case, the viscosity ratio after storage at room temperature 48H was about 1.7 times the initial ratio, and was not inferior to Comparative Example 1. In particular, when a silane coupling agent (KBM-403) was used as a curing aid, the rate of increase in viscosity after 6H was within 5% of the initial ratio.

As described above, in an aluminum chelate-organosilane compound (arylsilanol, silane coupling agent) curing system, a curing system in which a part of the organosilane compound is replaced with a boric acid ester is cured compared to a curing system using only the organosilane compound. It is possible to lower the starting temperature. In addition, by using a latent curing agent having a high potential, which is surface-treated with an alkylalkoxysilane, a thermosetting epoxy resin composition exhibiting a good liquid life at room temperature as well as low temperature activation can be prepared. It becomes possible.

Since the thermosetting epoxy resin composition of the present invention has excellent low-temperature curability while suppressing an increase in viscosity during storage, it can be suitably used as, for example, an epoxy-based adhesive for low-temperature and short-time connection. .

Claims

Epoxy resin,
A latent curing agent composed of polyurea resin and porous particles holding aluminum chelate;
A thermosetting epoxy resin composition comprising boric acid.
The thermosetting epoxy resin composition according to claim 1, further comprising an organosilane compound.
The thermosetting epoxy resin composition according to claim 2, wherein the organic silane compound contains at least one of an arylsilanol compound and a silane coupling agent.
The boric acid is derived from a boric acid ester in preparing the thermosetting epoxy resin composition,
When preparing the thermosetting epoxy resin composition, the mass ratio of the organosilane compound to the borate ester (organosilane compound: borate ester) is 1: 3 to 3 The thermosetting epoxy resin composition according to claim 2, wherein the thermosetting epoxy resin composition is 1.
The thermosetting epoxy resin composition according to any one of claims 1 to 4, wherein the epoxy resin contains an alicyclic epoxy resin.
The thermosetting epoxy resin composition according to claim 5, wherein the alicyclic epoxy resin contains at least one of compounds represented by the following structural formulas.
The thermosetting epoxy resin composition according to any one of claims 1 to 6, wherein the porous particles further contain a vinyl resin as a constituent component.
The thermosetting epoxy resin composition according to any one of claims 1 to 7, wherein the surface of the porous particles has a reaction product of an alkoxysilane coupling agent.
A method for producing a thermosetting epoxy resin composition according to any one of claims 1 to 8,
The manufacturing method of the thermosetting epoxy resin composition characterized by including the mixing process which mixes the said epoxy resin, the said latent hardener, and boric acid ester.
The method for producing a thermosetting epoxy resin composition according to claim 9, wherein an organic silane compound is further mixed in the mixing step.
The thermosetting epoxy resin according to claim 10, wherein a mass ratio of the organosilane compound to the borate ester (organosilane compound: borate ester) in the mixing step is 1: 3 to 3: 1. A method for producing the composition.